The present invention relates generally to piezo-resonator structures, and is particularly directed to a piezo-electric ceramic resonator in which the resin which accumulates during the formation of the outer shell is prevented from entering the resonator frame.
Piezo-resonator structures are a matter of well known prior art. In general, piezo-resonators are constructed by inserting a ceramic resonator into a cavity defined by an insulating frame and a plurality of metallic terminal strips. The terminal strips establish electrical contacts to the electrode surfaces of the resonator. The periphery of the resonator cavity is then coated with an insulating outer shell made of synthetic resin.
The above-described construction of the piezo-resonator is disadvantageous in that resin can leak into the resonator cavity at gaps between the terminal strips and the frame. This leakage of the resin into the resonator cavity results in the adhesion of the resin to the resonator which restricts the vibratory oscillations of the resonator and degrades the resonator performance thereby. Since such degraded performance cannot be tolerated, these cavity piezo-resonators must be discarded, which greatly increases production costs.